The patch titled Subject: mm: swap: fix potensial buffer overflow in setup_clusters() has been added to the -mm mm-new branch. Its filename is mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch
This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...
This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------ From: Kemeng Shi shikemeng@huaweicloud.com Subject: mm: swap: fix potensial buffer overflow in setup_clusters() Date: Thu, 22 May 2025 20:25:53 +0800
In setup_swap_map(), we only ensure badpages are in range (0, last_page]. As maxpages might be < last_page, setup_clusters() will encounter a buffer overflow when a badpage is >= maxpages.
Only call inc_cluster_info_page() for badpage which is < maxpages to fix the issue.
Link: https://lkml.kernel.org/r/20250522122554.12209-4-shikemeng@huaweicloud.com Fixes: b843786b0bd01 ("mm: swapfile: fix SSD detection with swapfile on btrfs") Signed-off-by: Kemeng Shi shikemeng@huaweicloud.com Cc: stable@vger.kernel.org Cc: Baoquan He bhe@redhat.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Kairui Song kasong@tencent.com Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/swapfile.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
--- a/mm/swapfile.c~mm-swap-fix-potensial-buffer-overflow-in-setup_clusters +++ a/mm/swapfile.c @@ -3208,9 +3208,13 @@ static struct swap_cluster_info *setup_c * and the EOF part of the last cluster. */ inc_cluster_info_page(si, cluster_info, 0); - for (i = 0; i < swap_header->info.nr_badpages; i++) - inc_cluster_info_page(si, cluster_info, - swap_header->info.badpages[i]); + for (i = 0; i < swap_header->info.nr_badpages; i++) { + unsigned int page_nr = swap_header->info.badpages[i]; + + if (page_nr >= maxpages) + continue; + inc_cluster_info_page(si, cluster_info, page_nr); + } for (i = maxpages; i < round_up(maxpages, SWAPFILE_CLUSTER); i++) inc_cluster_info_page(si, cluster_info, i);
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Patches currently in -mm which might be from shikemeng@huaweicloud.com are
mm-shmem-avoid-unpaired-folio_unlock-in-shmem_swapin_folio.patch mm-shmem-add-missing-shmem_unacct_size-in-__shmem_file_setup.patch mm-shmem-fix-potential-dead-loop-in-shmem_unuse.patch mm-shmem-only-remove-inode-from-swaplist-when-its-swapped-page-count-is-0.patch mm-shmem-remove-unneeded-xa_is_value-check-in-shmem_unuse_swap_entries.patch mm-swap-move-nr_swap_pages-counter-decrement-from-folio_alloc_swap-to-swap_range_alloc.patch mm-swap-correctly-use-maxpages-in-swapon-syscall-to-avoid-potensial-deadloop.patch mm-swap-fix-potensial-buffer-overflow-in-setup_clusters.patch mm-swap-remove-stale-comment-stale-comment-in-cluster_alloc_swap_entry.patch